Biomedical subjects

T J Marrie

Publications and source records attributed to T J Marrie.

At least 145 records · Page 8Linked to original sources

PubMed1986

Are health care workers at risk for infection during an outbreak of nosocomial Legionnaires' disease?

We studied data from 500 health care workers to answer the question: Are health care workers at risk for infection during an outbreak of nosocomial Legionnaires' disease? These workers were employed at a hospital where eight cases of nosocomial Legionella pneumophila serogroup 1 pneumonia occurred over a 4-week period. The source was potable water. Acute-phase blood samples were collected on the day the water supply was decontaminated, convalescent samples were collected 4 to 6 weeks later from 373 subjects, and a single serum sample was obtained from an additional 127 subjects. Antibody titers to L. pneumophila were determined by an indirect immunofluorescent antibody (IFA) technique and by a microagglutination assay with the epidemic strain as the test antigen. Subjects who had an IFA titer of greater than or equal to 1:256 were retested with an anti-human IgM conjugate. None of the 373 health care workers had a fourfold rise in antibody titer. The geometric mean antibody titer of 73.8 for the 500 health care workers was significantly higher than that of 68.1 for 976 blood donors (p less than 0.01). Only 2.4% had recent infection as evidenced by a microagglutination test, despite the fact that 84% were susceptible. We conclude that in the setting of a short-term outbreak of Legionnaires' disease caused by contaminated potable water the risk of infection among health care workers is low: 2.4% or less.

Adult↗

PubMed1986

Nursing home-acquired pneumonia. A case-control study.

To determine if there are any unique features of nursing home-acquired pneumonia we carried out a case-control study wherein each patient admitted with nursing home-acquired pneumonia was age- and sex-matched with a patient with community-acquired pneumonia. There were 36 men and 38 women in the nursing home group. The mean age of both groups was 74 years. The mortality rate for nursing home-acquired pneumonia it was 40.5%, whereas for community-acquired pneumonia it was 28% (P = NS). Patients with nursing home-acquired pneumonia had a significantly higher incidence of dementia and cerebrovascular accidents, and patients with community-acquired pneumonia were more likely to be smokers and to have chronic obstructive pulmonary disease. Aspiration pneumonia was more common among patients with nursing home-acquired pneumonia (P less than .001), and Hemophilus influenza pneumonia more common among the patients with community-acquired infection (P less than .01). Sputum for culture could be obtained in only 31 and 39% of the patients--contributory to the high rates of pneumonia of unknown etiology 63.5 and 56.1% for the nursing home group and the control subjects, respectively. Patients with nursing home-acquired pneumonia received cloxacillin and aminoglycosides more frequently than patients with community-acquired pneumonia (P less than .05), and patients with community-acquired pneumonia received erythromycin more frequently than patients with nursing home-acquired pneumonia (P less than .05). Complications were common during the hospital stay of these patients--the most frequent being congestive heart failure, urinary tract infection, renal failure, and respiratory failure.

Age Factors↗

PubMed1986

Survey of anaerobic susceptibility patterns in Canada.

The in vitro activity of penicillin, cefoxitin, moxalactam, ticarcillin, clindamycin, chloramphenicol, and metronidazole against 590 anaerobic isolates collected from five Canadian hospitals during 1984 was determined by an agar dilution technique. Cefoxitin, clindamycin, chloramphenicol, and metronidazole were very active against most of the isolates. No major regional differences in the susceptibility patterns were observed.

Bacteria, Anaerobic↗

PubMed1986

Nosocomial pulmonary infection: possible etiologic significance of bacterial adhesion to endotracheal tubes.

Biomaterials are essential for life support and monitoring of critically ill patients, but their use increases the risk of nosocomial infection. Of the various plastics used for life support and monitoring devices, polyvinylchloride is one to which bacteria most readily adhere. Through the use of qualitative culture techniques and scanning and transmission electron microscopy, we studied the surfaces of polyvinylchloride endotracheal tubes removed from 25 ICU patients, to determine if bacterial adhesion to those tubes was sufficient to provide a possible source for repeated contamination of the tracheobronchial tree. Of the surfaces studied, 16% were partially covered and 84% were completely covered by an amorphous bacteria-containing matrix. Some biofilm-enclosed bacterial aggregates projected from the matrix into the lumen of the tube. The mechanism by which endotracheal tubes repeatedly inoculate the lungs of intubated patients may prove to be dislodgment of such aggregates by suction apparatus.

Adult↗

PubMed1985

Antibiotic resistance of Pseudomonas aeruginosa colonizing a urinary catheter in vitro.

A modified Robbins Device was used to establish coherent biofilms of Pseudomonas aeruginosa on the surface of catheter material in an artificial urine milieu and the ability of an antibiotic to penetrate the biofilm and kill the enclosed bacteria was assessed. The Pseudomonas aeruginosa strain used had been isolated from a patient with urinary tract infection. Although planktonic (floating) cells of the Pseudomonas aeruginosa strain were inhibited by less than 1 mg/l of tobramycin and killed by 50 mg/l, contact with 1,000 mg/l of tobramycin for 12 h failed to kill all the sessile (adherent) bacteria in the biofilms on the surface of the catheter material. Surviving sessile bacteria recovered directly from the exposure to 1,000 mg/l of tobramycin were inhibited by 0.4 mg/l of this agent when tested as dispersed planktonic cells by standard MIC methods. It is suggested that growth within thick adherent biofilms confers upon cells of Pseudomonas aeruginosa a large measure of resistance to aminoglycosides and other antibiotics that may help to explain the frequent failure of antibiotic chemotherapy in catheter-associated urinary tract infections.

Anti-Bacterial Agents↗

PubMed1985

Pneumonia and meningo-encephalitis due to Coxiella burnetii.

We describe the case of a 35-year-old man who presented with pneumonia and encephalitis due to Coxiella burnetii. The neurological manifestations of Q fever are discussed and we suggest that C. burnetii be included in the differential diagnosis of patients with pneumonia and encephalitis.

Adult↗

PubMed1985

Community-acquired pneumonia requiring hospitalization. Is it different in the elderly?

The authors studied 138 patients, 57 of whom were younger than 65 years of age and 81 who were 65 years of age and older, with community-acquired pneumonia to determine whether or not such pneumonia is different in the elderly and to define how such patients are investigated and treated. Pneumonia in the elderly was characterized by a higher mortality, 30 v 10%; more likely to be of unknown etiology, 54 v 30%; and more likely to show radiographic progression after the patient had been admitted to the hospital, 48 v 11%. In addition, elderly patients were more likely to be afebrile when admitted, 57 v 26%. Twenty-seven etiologic categories were present in 77 patients in whom a cause for the pneumonia was established. Streptococcus pneumoniae accounted for 9.4% of the pneumonia overall and for 27% of the pneumonia among patients who had sputum cultures performed before antibiotic therapy. The diagnostic yield was 11.6% for blood cultures, 38.2% for sputum cultures, 2.3% for throat washing, and 22.1% for serological studies. Twenty-seven percent of patients were receiving antibiotics of the time of admission to the hospital. Most (79%) received more than one antibiotic after admission. This study indicates that community-acquired pneumonia is a serious illness and that an algorithm approach to diagnosis and treatment of such pneumonia is necessary.

Aged↗

PubMed1985

Mode of growth of bacterial pathogens in chronic polymicrobial human osteomyelitis.

Direct examination of material from two cases of persistent (2 and 60 years) osteomyelitis by morphological and culture techniques showed that the pathogens comprised several bacterial species whose cells grew predominantly in discrete exopolysaccharide-enclosed microcolonies made up of a single bacterial morphotype. Bacterial microcolonies were seen between tissue elements in infected connective tissue, and the microcolonies adherent to bone surfaces coalesced to form extensive biofilms that occluded the surfaces of dead bone in sequestrae. Decalcification techniques were required to examine the interior of infected bone, but recognizable remnants were associated with very large amounts of fibrous, ruthenium red-stained material. All bacterial growth in these persistent infections occurred within an intercellular matrix, and some elements of this matrix, which was fibrous in transmission electron microscopy and amorphous in scanning electron microscopy, were associated with the surfaces of bacterial cells in a manner that suggested their production by these organisms. All of the implications of this microcolony mode of bacterial growth in osteomyelitis, and in other chronic bacterial diseases, have yet to be determined.

Adult↗

PubMed1985

Seroepidemiology of Q fever among domestic animals in Nova Scotia.

We used the indirect microimmunofluorescence test to determine the presence of antibodies in sheep, cattle, goat, cat, and dog sera to phase I and II Coxiella burnetii antigens in Nova Scotia. Only 6.7 per cent of the 329 sheep tested had antibodies to phase II antigen and none had antibodies to phase I. Of 29 goats tested, 7 per cent and 3.5 per cent had antibodies to phase II and phase I antigens, respectively. In contrast, 23.8 per cent of the 214 cattle tested had antibodies to phase II antigen, and 24.2 per cent had antibodies to phase I antigen; 24.1 per cent of 216 cats tested had antibodies to phase II antigen and 6 per cent had antibodies to phase I antigen. None of the 447 dogs tested had antibodies detected. We conclude that cattle and cats may be reservoirs for human Q fever in Nova Scotia.

Animals↗

PubMed1985

Does cytomegalovirus play a role in community-acquired pneumonia?

Cytomegalovirus (CMV) is recognized as an important pathogen in the immuno-suppressed patient. Sporadic case reports of cytomegalovirus community-acquired pneumonia have appeared. We studied 443 patients with community-acquired pneumonia requiring hospitalization to define the role of cytomegalovirus in this illness. Four patients (0.9%) had good evidence that cytomegalovirus caused their pneumonia: 2 had the virus isolated from pulmonary tissue and 2 had cytomegalovirus inclusion bodies visualized in this tissue. An additional 14 patients had serologic evidence (a fourfold rise in the complement fixation tests) of cytomegalovirus infection. Analysis of these 18 patients suggest, that cytomegalovirus plays a role in community-acquired pneumonia. Six (33%) of the patients were immunosuppressed. Six others had concomitant infections: Chlamydia trachomatis (3); Epstein-Barr virus and M. pneumoniae (1); and bacteremia with Group B streptococcus and Bacteroides fragilis plus Eubacterium lentum (1 each). Seven patients (39%) required assisted ventilation, four of whom developed secondary bacterial pneumonia. Five (28%) died. Only two patients had a clinical and radiographic picture suggestive of a viral illness as a cause of the pneumonia. Three patients had atypical lymphocytes in their peripheral blood film. We found that the prevalence of complement fixing antibody to cytomegalovirus increased with age. Such antibody was lacking among those in the 16-20 year group while it peaked at 65% for males and at 78% for females ages 91-100 years. Despite the fact that 42.2% of the adults lacked antibody to cytomegalovirus, community-acquired pneumonia due to this virus is uncommon and does not justify routine serological testing for such infection among patients with community-acquired pneumonia.

Adult↗

PubMed1984

Isolation of Legionella pneumophila from the blood of a patient with Legionnaires' disease.

Legionella pneumophila is rarely isolated from blood cultures. Presently most cases of Legionnaires' disease are diagnosed retrospectively from the results of indirect fluorescent antibody tests, which possess inherent disadvantages. An 81-year-old woman with a history of diabetes mellitus presented symptoms of Legionnaires' disease. Five hours before her death 1.5 mL of blood was withdrawn from a scalp vein and seeded to a culture medium. Following incubation for 3 days L. pneumophila serotype 1 was isolated.

Aged↗

PubMed1984

Cleaning of anaesthesia breathing circuits and tubings: a Canadian survey.

A cross-Canada survey of 38 university-affiliated hospitals with over 250 beds was undertaken to examine the procedures for cleaning anaesthetic tubings and circuits. Twenty-eight (74 per cent) hospitals responded. Gluteraldehyde was the most commonly used method (13/28), and pasteurization was the second most used method (9/28). These two methods are described and recommendations are made for basic requirements for disinfection.

Anesthesiology↗

PubMed1984

Ultrastructure of Candida parapsilosis endocarditis.

We used light microscopy and scanning and transmission electron microscopy to study the structure of Candida parapsilosis vegetations on five surgically removed porcine bioprosthetic valves. Scanning electron microscopy revealed a "mossy" amorphous surface. In some areas, C. parapsilosis cells could be seen below the surface layer. In areas in which the vegetation had cracked, myriads of healthy C. parapsilosis cells were seen to be loosely adherent to one another. These cells were covered with a flocculent or fibrillar matrix. A compact intercellular matrix was evident by transmission electron microscopy. Hyphal elements were seen invading valvular tissue. The loose matrix that bound large clumps of C. parapsilosis cells explains why large emboli are frequent complications of Candida endocarditis.

Bioprosthesis↗

PubMed1984

Scanning and transmission electron microscopy of in situ bacterial colonization of intravenous and intraarterial catheters.

Intravenous and intraarterial catheters were examined microbiologically and morphologically. Bacteria or yeasts were recovered from 38 of the 63 catheters examined, and Staphylococcus epidermidis was present on 29 of the 38 colonized catheters. Examination of unused Teflon catheters ( Jelco ; Surgikos , Inc., Peterborough , Ontario, Canada) showed surface irregularities, and the examination of colonized intravascular catheters recovered from patients showed very extensive amorphous accretions on both their lumenal and external plastic surfaces. Detailed scanning electron microscope examination of the accretions on vascular catheters from which S. epidermidis had been isolated showed (ca. 0.8 micron) coccoid bacteria within confluent biofilms , in which they were enveloped by amorphous material. Transmission electron microscope examination of these same accretions revealed coccoid cells (ca. 0.8 micron) with a gram-positive cell wall structure living in fibrous matrix-enclosed microcolonies in spaces between squamous epithelial cells. Staphylococcus aureus biofilms were seen to contain coccoid cells (ca. 1 micron) in a very extensive amorphous matrix, and a Candida parapsilosis biofilm contained very large numbers of large coccoid cells (ca. 4.3 microns) in a fibrous matrix resembling fibrin. Cells of a Corynebacterium species appeared to form much less extensive matrix-enclosed microcolonies on the colonized plastic surface. These data indicate bacteria and yeasts colonize intravascular catheters by an adherent biofilm mode of growth on these plastic surfaces.

Bacteria↗

PubMed1984

Morphology of bacterial attachment to cardiac pacemaker leads and power packs.

The mode of growth of the bacteria adherent to the surfaces of various components of cardiac pacemakers infected with coagulase-negative staphylococci was examined by scanning and transmission electron microscopy. Within developing adherent microcolonies, coccoid cells could be clearly seen to be enveloped by an amorphous material that condensed radically upon dehydration for electron microscopy, producing an amorphous residue in scanning electron micrographs and a fibrous anionic ruthenium red-staining residue in transmission electron micrographs. The differences in morphologies of the condensed residues may reflect differences in exopolysaccharides elaborated by the microorganisms and the degree to which materials of host origin are incorporated. The coccoid cells of coagulase-negative staphylococci were less clearly seen in thick, mature, adherent biofilms on heavily colonized surfaces because the condensed residue of their exopolysaccharide glycocalyces covered, and sometimes occluded, the bacteria cells. These coagulase-negative staphylococcal strains appeared to produce more exopolysaccharide material than did the strains infecting various intravascular catheters.

Adhesiveness↗

PubMed1984

Seroepidemiology of Q fever in Nova Scotia and Prince Edward Island.

The prevalence of Coxiella burnetti infection (Q fever) was determined among Nova Scotia (N.S.) and Prince Edward Island (P.E.I.) blood donors by using the complement fixation and microimmunofluorescence (IF) test. The complement fixation and IF antibody tests measured antibody prevalence for the phase II or phase I and II antigens, respectively. Complement-fixing antibodies to phase II antigen were detected in 4.1% of 997 N.S. and 5.0% of 219 P.E.I. blood donors. Anti-phase II antibodies were detected by microimmunofluorescence in 11.8 and 14.6% of the blood donors in the two provinces, respectively. Anti-phase I antibodies were detected among 2.8% of the N.S. blood donors and 6.3% of the P.E.I. blood donors. Comparison of rates of anti-phase II IF by counties in N.S. revealed that there was at least one county where infection by C. burnetti is hyperendemic. Rates of antibody prevalence were similar in all three areas of P.E.I. examined. We conclude that "Q fever" is endemic in N.S. and P.E.I. and that the microimmunofluorescence test is more suitable than the complement fixation test for seroepidemiologic studies.

Adolescent↗

PubMed1984

The radiographic features of epidemic and sporadic Q fever pneumonia.

Radiographic dissimilarities exist between the chest radiographs of patients with epidemic and sporadically-occurring Q fever pneumonia. Chest radiographs of 25 patients with Q fever pneumonia were retrospectively assessed, and demonstrated previously unreported differences between these two broad groups. Differing strains of Coxiella burnetii, or varying doses of the pathogen, are postulated as the pathogenetic mechanisms for the observed discrepant findings.

Adult↗

PubMed1984

Computed tomographic scanning in Listeria monocytogenes meningitis.

Seven adults with Listeria monocytogenes infection of the central nervous system had computed X-ray tomography of the head performed. One patient had a normal scan, three had hydrocephalus; cerebral edema, an arachnoid cyst and hyperemia were each noted in one patient. Atrophy of the vermis of the cerebellum was demonstrated on follow-up scans in two patients. Further studies are necessary to determine whether such atrophy is a frequent sequelae of L. monocytogenes central nervous system infection.

Adult↗